Power Tool with Peristaltic Pump

ABSTRACT

The present invention in one embodiment is a power tool including a housing, a main power shaft located within the housing, a peristaltic pump assembly positioned within the housing and operably connected to the main power shaft, and an outlet conduit operably connected to the peristaltic pump assembly and extending between the peristaltic pump assembly and an outlet port in the housing such that fluid is forced by the peristaltic pump assembly through the outlet conduit to a location outside of the housing.

FIELD OF THE INVENTION

The present invention relates to power tools and more particularly topower tools which generate dust or debris during normal operation of thepower tool.

BACKGROUND

Power tools are commonly used in various applications which generatesignificant amounts of dust or debris. By way of example, power toolsare used to shape work pieces such as wood, drywall, etc. In many cases,a user marks the work piece so as to guide shaping of the work pieces.Thus, a line may be used to indicate where the work piece is to be cut.In some instances, the mark is only used to initially align the workpiece with the power tool. Thereafter, the power tool is operated in aconstrained manner such that the desired cut is almost automaticallymade. For example, a mark may initially be aligned with a blade on atable saw and thereafter a guide is used to precisely maneuver the workpiece into contact with the blade.

In the forgoing example, once the work piece makes contact with theblade, the guide mark may be obscured by saw dust generated by theblade. In such cases, obscuration of the guide mark by saw dust may notbe overly problematic. Nonetheless, many users still desire to see theguide mark as the cut is being made, if only to give a sense of securitythat the work piece has not become misaligned.

In other instances, a user actively modifies the alignment during ashaping operation. By way of example, jig saws and saber saws arecommonly used to make curved cuts in a work piece. Accordingly, the useris constantly modifying the alignment of the power tool with respect tothe work piece to follow the curved guide mark. In this type ofscenario, obscuration of a guide mark by saw dust may result in a poorcut thereby requiring additional shaping operations or even ruining thework piece.

In some systems, removal of saw dust from an area that is being shapedis accomplished either by reliance upon air movement resulting frommovement of the shaping component, such as a saw blade, or by a motorfan that is attached directly to the main power shaft of the tool andconfigured such that some of the air from the motor fan is directedtoward a work piece. Such approaches may be unsatisfactory for a numberof reasons. In some instances, the shaping component simply does notgenerate sufficient airflow to clear the saw dust. In tools including amotor fan, the motor fan is primarily configured to cool the motor.Accordingly, configuring the motor fan to further clear saw dust anddebris severely limits the design of the tool.

Various alternatives are available to remove debris formed by theshaping operation in addition to those discussed above. Some power toolsemploy vacuum systems connected to the tool to remove cutting debris.The use of a vacuum system, however, often makes control of the toolmore cumbersome, and the vacuum system itself can greatly increase thecost and complexity of a power tool. In other systems, a bellows is usedto generate bursts of air which can be directed at the work piece. Whilesuch systems can be effective, the pulsed air flow can be distracting.Additionally, the reciprocating nature of the bellows activationmechanism may introduce undesired vibrations into the power tool.

Accordingly, there is a need for a power tool that allows increasedvisibility at the point of a shaping operation. A power tool that allowsincreased visibility at the point of a shaping operation without areciprocating activation mechanism would be further beneficial.

SUMMARY

The present invention in one embodiment is a power tool including ahousing, a main power shaft located within the housing, a peristalticpump assembly positioned within the housing and operably connected tothe main power shaft, and an outlet conduit operably connected to theperistaltic pump assembly and extending between the peristaltic pumpassembly and an outlet port in the housing such that fluid is forced bythe peristaltic pump assembly through the outlet conduit to a locationoutside of the housing.

In a further embodiment, a power tool includes a housing, a main powershaft at least partially located within the housing, a peristaltic pumpassembly operably connected to the main power shaft, and an outletconduit operably connected to the peristaltic pump assembly andextending between the peristaltic pump assembly and an outlet portion ofthe outlet conduit, the outlet portion configured to direct fluid towarda predetermined location.

These and other advantages and features of the present invention may bediscerned from reviewing the accompanying drawings and the detaileddescription of a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may take form in various system and methodcomponents and arrangement of system and method components. The drawingsare only for purposes of illustrating exemplary embodiments and are notto be construed as limiting the invention.

FIG. 1 depicts a simplified side cross-sectional view of a hand powertool incorporating features of the present invention with a peristalticpump assembly operably connected to an end portion of a main power shaftopposite to the end portion of the main power shaft which is used todrive a shaping component;

FIG. 2 depicts a top cross-sectional view of the peristaltic pumpassembly of FIG. 1;

FIG. 3 depicts a simplified side cross-sectional view of a hand powertool incorporating features of the present invention with a peristalticpump assembly operably connected to the same end portion of a main powershaft which is used to drive a shaping component;

FIG. 4 depicts a side cross-sectional view of a diaphragm check valve ina closed position;

FIG. 5 depicts a side cross-sectional view of the diaphragm check valveof FIG. 4 in an open position;

FIG. 6 depicts a top cross-sectional view of a peristaltic pump assemblyincorporating four of the check valves of FIG. 4 arranged to force fluidout of an outlet conduit regardless of the direction of rotation of theperistaltic pump assembly with the check valves in the positionsresulting from a clockwise rotation of the pump shaft; and

FIG. 7 depicts a top cross-sectional view of the peristaltic pumpassembly of FIG. 6 with the check valves in the positions resulting froma counter-clockwise rotation of the pump shaft.

DESCRIPTION

A hand power tool generally designated 100 is shown in FIG. 1. In theembodiment of FIG. 1, the power tool 100 includes a main housing portion102. The main housing portion 102 houses a motor 104 and controlelectronics 106 for control of the power tool 100. The main housingportion 102 in one embodiment includes a battery receptacle forreceiving a rechargeable battery pack (not shown). In one embodiment,the rechargeable battery pack (not shown) comprises a lithium-ionbattery. The power tool 100 in other embodiments is powered by anexternal power source such as an external battery or a power cord.

The motor 104 is configured to selectively cause a main power shaft 108to rotate. The main power shaft 108 in the embodiment of FIG. 1 islocated completely within the housing 102. In other embodiments, aportion of the main power shaft 108 extends outwardly of the housing. Amotor fan 110 is fixedly attached to the main power shaft 108 andconfigured to force cooling air against the motor 104 during operationof the power tool 100.

A shaping component 112, which in this embodiment is a circular blade,is operably connected to the main power shaft 108 by a shaping componentgear 114 which is enmeshed with an end portion 116 of the main powershaft 108. The shaping component gear 114 is fixedly attached to ashaping component drive shaft 118 to which the shaping component 112 isremovably attached by a bolt 120 and clamping assembly 122. In theembodiment of FIG. 1, the power tool 100 is configured for operablydriving the shaping component 112 such that the shaping component 112rotates about the shaping component drive shaft 118. In otherembodiments, the power tool is configured to oscillate the shapingcomponent which may be formed as a straight saw blade, for example.

The housing portion 102 includes an outlet port 124 located proximate tothe location at which the shaping component drive shaft 118 extendsoutwardly of the housing 102. An end portion 126 of an outlet conduit128 extends through the outlet port 124 and is directed generally alongthe shaping component 112. End portion 126 in some embodiments is adirectional component that stops close to the housing or a flexible hoseor tubing piece. The outlet conduit 128 extends along and within thehousing 102 to a peristaltic pump assembly 140. The outlet conduit 128is in fluid communication with the peristaltic pump assembly 140 whichis described with additional reference to FIG. 2.

The peristaltic pump assembly 140 includes a pump gear 142 which isenmeshed with an end portion 144 of the main power shaft 108. The pumpgear 142 is fixedly attached to a pump shaft 146 which is fixedlyattached to a rotor 148. Two rollers 150/152 are rotatably supported bythe rotor 148 through axles 154/156, respectively. The rollers 150/152are configured to extend outwardly from the rotor 148 so as to contactan elastomeric tube 160. The elastomeric tube 160 includes an inletportion 162 and an outlet portion 164. The elastomeric tube 160 extendsabout an arcuate pump casing 166 which in this embodiment is formed onthe inner surface of the housing 102.

In operation, a user activates the power tool 100 such as by use of apower switch (not shown) and the control electronics 106 causes power tobe applied to the motor 104. The motor 104 then causes the main powershaft 108 to rotate. In the embodiment of FIG. 1, the left side of themain power shaft 108, as depicted in FIG. 1, rotates out of the pagewhile the right side of the power shaft 108 rotates into the page.

Rotation of the main power shaft 108 causes the shaping component gear114 to rotate in an opposite direction. Thus, the right side of theshaping component gear 114, as depicted in FIG. 1, rotates out of thepage while the left side of the shaping component gear 114 rotates intothe page. Since the shaping component drive shaft 118 is fixedlyattached to the shaping component gear 114, the shaping component driveshaft 118 rotates in the same manner as the shaping component gear 114.Similarly, since the shaping component 112 is attached to the shapingcomponent drive shaft 118, the shaping component 112 also rotates in thesame manner as the shaping component gear 114.

Rotation of the main power shaft 108 further causes the pump gear 142 torotate in an opposite direction. Thus, the right side of the pump gear142, as depicted in FIG. 1, rotates out of the page while the left sideof the pump gear 142 rotates into the page. Since the pump shaft 146 isfixedly attached to the pump gear 142, the pump shaft 146 rotates in thesame manner as the pump gear 114. Similarly, since the rotor 148 isfixedly attached to the pump shaft 146, the rotor 148 also rotates inthe same manner as the pump gear 142. This results in a clockwiserotation of the rotor 148 as viewed in FIG.2, as indicated by the arrow180.

As the rotor 148 rotates in the direction indicated by the arrow 180,the rollers 150 and 152 are forced in the direction of the arrows 182and 184, respectively. The rollers 150 and 152 extend outwardly of therotor 148 and are in contact with the elastomeric tube 160. Accordingly,as the rollers 150/152 are forced in the direction of the arrows 182 and184, the rollers “roll” along the stationary elastomeric tube 160 andsqueeze the elastomeric tube 160 against the arcuate pump casing 166. Inthe embodiment of FIG. 1, the rollers 150/152, rotor 148, elastomerictube 160 and arcuate pump casing 166 are sized such that the elastomerictube 160 is totally occluded at locations directly between the rollers150/152 and the arcuate pump casing 166 (see FIG. 1). In otherembodiments, the components are sized to provide only partial occlusion.

As the roller 150 moves toward the tube outlet 164 from the locationdepicted in FIG. 2, fluid within the elastomeric tube 160 between theroller 150 and the tube outlet 164 is forced through the elastomerictube 160 and out of the tube outlet 164 as indicated by the arrow 186.The fluid is then forced into the outlet conduit 128 which is in fluidcommunication with the tube outlet 164. In one embodiment, the outletconduit 128 is integrally formed with the elastomeric tube 160.

The fluid that is forced into the outlet conduit 128 flows out of theend portion 126 as indicated by the arrow 188 of FIG. 1. In theembodiment of FIG.1, the end portion 126 is located adjacent to theshaping component 112. In some embodiments wherein the fluid that ispumped is air, the end portion 126 is oriented such that the air flowwill impact the area of a work piece that is being shaped by the shapingcomponent 112, taking into account the effect of the movement of theshaping component 112. In embodiments wherein the fluid that is pumpedis a liquid, the end portion 126 may be oriented such that the liquidcontacts the shaping component 112, thereby cooling the shapingcomponent 112.

Returning to FIG. 2, as the roller 150 forces fluid out of the tubeoutlet 164, the roller 152 forces fluid within the elastomeric tube 160between the roller 150 and the roller 152 in the direction of the arrow190. Accordingly, when the roller 150 moves past the tube outlet 164,the fluid between the roller 150 and the roller 152 is forced out of thetube outlet 164. Because the rollers 150/152 are located generallyopposite to one another on the rotor 148, a substantially continuousstream of fluid is forced out of the tube outlet 164. In embodimentswhere a substantially continuous stream of fluid is not desired, asingle roller may be used. In single roller embodiments, the distancebetween the inlet and the outlet portions of the tube along the arcuatepump casing may be modified to provide the desired interruption in theeffluent stream. In embodiments with more than two rollers, the rollersare preferably equally spaced about the rotor.

Continuing with FIG. 2, the elastomeric tube 160 is made of a materialwhich regains its shape once the pressure applied by the rollers 150/152is removed at a particular location. Some commonly used elastomersinclude silicone, PVC, EPDM+polypropylene (as in SANTOPRENE),polyurethane and NEOPRENE. Extruded fluoropolymer tubes such as FKM(Viton, Fluorel, etc.) may also be used. Accordingly, as the roller 152moves away from the tube inlet 162, the elastomeric tube 160 regains itsshape, thus creating a vacuum which allows additional fluid to be forcedinto the elastomeric tube 160 through the tube inlet 162 behind theroller 152 as indicated by the arrow 192.

The elastomeric tube 160 is thus refilled with fluid until the roller152 collapses the elastomeric tube 160 at a location adjacent to thetube inlet 162. In some embodiments, a filter (not shown) is used tofilter fluid which comes through the tube inlet 162. The tube inlet 162may be configured to take a suction within the housing 102 or fromoutside of the housing 102. By positioning the tube inlet 162 next tothe motor 104, the effectiveness of the motor fan 110 may be increased.In embodiments wherein the fluid is a liquid, the tube inlet 162 may beimmersed within a liquid reservoir.

While the invention is shown in one configuration in the embodiment ofFIG. 1, the invention may be modified in a number of ways to supportdifferent designs. By way of example, FIG. 3 depicts a tool 200 whichincludes a main housing portion 202. The main housing portion 202 housesa motor 204 and control electronics 206 for control of the power tool200. The motor 204 is configured to selectively cause a main power shaft208 to rotate. A shaping component 212 is operably connected to the mainpower shaft 208 by a shaping component gear 214 which is enmeshed withan end portion 216 of the main power shaft 208.

The housing portion 202 includes an outlet port 224 located proximate tothe location at which a shaping component drive shaft 218 extendsoutwardly of the housing 202. An end portion 226 of an outlet conduit228 extends through the outlet port 224 and is directed generally alongthe shaping component 212. The outlet conduit 228 extends within thehousing 202 to a peristaltic pump assembly 240.

The outlet conduit 228 is in fluid communication with the peristalticpump assembly 240 which is substantially the same as the peristalticpump assembly 140 of FIG. 2. The main difference is that the pump gear242 is enmeshed with the end portion 216 of the main power shaft 208 ata location substantially opposite to the side of the main power shaft208 whereat the shaping component gear 214 is enmeshed with the mainpower shaft 208.

In addition to modification of the physical location of the peristalticpump assembly within or outside of the housing of a power tool, thefunction of the peristaltic pump assembly may be modified. As discussedabove, in some embodiments the tube inlet to the peristaltic pumpassembly is positioned to increase the effectiveness of a motor fan. Inother embodiments, the tube outlet or outlet conduit is positioned toprovide cooling directly to the motor of the power tool. In theseembodiments, the tube inlet is typically not positioned to also takesuction from the motor location.

While the embodiments of FIGS. 1 and 3 are power tools which rotatablydrive a shaping component in only a single direction, in someembodiments, the main power shaft rotatably drives a shaping componentin alternate directions. In embodiments wherein the main power shaft canbe rotated in different directions, the peristaltic pump assembly isgenerally configured to produce the same flow of air through an outletconduit. One such embodiment incorporates diaphragm check valves such asthe check valve 250 depicted in FIGS. 4 and 5.

With initial reference to FIG. 4, the check valve 250 includes a seatportion 252 which is sealingly engaged with the inner wall 254 of a tube256. A resilient diaphragm 258 is positioned in the seat 252 andconfigured such that in the absence of any pressure from fluid withinthe tube 256 acting upon the diaphragm 258, the diaphragm 258 is seatedfirmly against the seat 252. Accordingly, if pressure is applied to thediaphragm 258 in the direction of the arrow 260, the diaphragm 258 ismore firmly seated against the seat 252 and no fluid is allowed to pass.

When pressure is applied in the direction of the arrow 262 of FIG. 5,however, the pressure resiliently deforms the diaphragm 258 forcing thediaphragm 258 away from the seat 252 as depicted in FIG. 5. Accordingly,the fluid providing the pressure is free to move past the seat 252 asindicated by the arrows 264/266.

With reference now to FIG. 6, a peristaltic pump assembly 280 includes apump shaft 282 which is fixedly attached to a rotor 284. Two rollers286/288 are rotatably supported by the rotor 284 through axles 290/292,respectively. An elastomeric tube 294 includes a first end portion 296and a second end portion 298. The elastomeric tube 294 extends about anarcuate pump casing 300.

An inlet 302 is in interruptible fluid communication with the first endportion 296 through a check valve 304. The inlet 302 is also ininterruptible fluid communication with the second end portion 298through a check valve 306. An outlet conduit 310 is in interruptiblefluid communication with the first end portion 296 through a check valve312. The outlet conduit 310 is also in interruptible fluid communicationwith the second end portion 298 through a check valve 314.

The peristaltic pump assembly 280 is configured to provide fluid flowoutwardly through the outlet conduit 310 regardless of the direction inwhich a main power shaft (not shown) operably connected to the pumpshaft 282 is turning. By way of example, if the main power shaft (notshown) is rotated such that the pump shaft 282 turns in the direction ofthe arrow 316 of FIG. 6, the roller 288 will force fluid out of thesecond end portion 298. The check valve 306 is arranged such that anincrease in pressure at the second end portion 298 causes the checkvalve 306 to be fully shut. Accordingly, no fluid passes through thecheck valve 306. The check valve 314, however, is arranged such that anincrease in pressure at the second end portion 298 causes the checkvalve 314 to open. Accordingly, fluid passes through the check valve314, resulting in a higher pressure at the outlet conduit 310.

At the same time that the roller 288 is forcing fluid out of the secondend portion 298, the elastomeric tube 294 is regaining its normal shapeas the roller 286 moves away from the first end portion 296, therebycreating a low pressure area at the first end portion 296. The resultantpressure drop from the higher pressure generated in the outlet conduit310 as described above, along with the low pressure at the first endportion 296 causes the check valve 312 to be firmly seated.Additionally, the low pressure at the first end portion 296 causes fluidfrom the inlet 302 to move through the check valve 304 to the first endportion 296.

Consequently, rotation of the pump shaft 282 in the direction of thearrow 316 causes suction at the inlet 302 through the check valve 304while fluid is emitted through the outlet conduit 310 by way of thecheck valve 314.

If the rotation of the pump shaft is reversed, the pump shaft 282 turnsin the direction of the arrow 318 of FIG. 7, and the roller 286 willforce fluid out of the first end portion 296. The check valve 304 isarranged such that an increase in pressure at the first end portion 296causes the check valve 304 to be fully shut. Accordingly, no fluidpasses through the check valve 304. The check valve 312, however, isarranged such that an increase in pressure at the first end portion 296causes the check valve 312 to open. Accordingly, fluid passes throughthe check valve 312, resulting in a higher pressure at the outletconduit 310.

At the same time that the roller 286 is forcing fluid out of the firstend portion 296, the elastomeric tube 294 is regaining its normal shapeas the roller 288 moves away from the second end portion 298, therebycreating a low pressure area at the second end portion 298. Theresultant pressure drop from the higher pressure generated in the outletconduit 310 as described above, along with the low pressure at thesecond end portion 298 causes the check valve 314 to be firmly seated.Additionally, the low pressure at the second end portion 298 causesfluid from the inlet 302 to move through the check valve 306 to thesecond end portion 298.

Consequently, rotation of the pump shaft 282 in the direction of thearrow 318 causes suction at the inlet 302 through the check valve 306while fluid is emitted through the outlet conduit 310 by way of thecheck valve 312.

Therefore, by the addition of check valves, a peristaltic pump assemblycan be configured to provide a stream of effluent through an outletconduit regardless of the direction of rotation of a pump shaft. Thus,the peristaltic pump assembly may be used with power tools which allowfor the direction of shaft rotation to be reversed.

While the present invention has been illustrated by the description ofexemplary processes and system components, and while the variousprocesses and components have been described in considerable detail,applicant does not intend to restrict or in any limit the scope of theappended claims to such detail. Additional advantages and modificationswill also readily appear to those skilled in the art. The invention inits broadest aspects is therefore not limited to the specific details,implementations, or illustrative examples shown and described.Accordingly, departures may be made from such details without departingfrom the spirit or scope of applicant's general inventive concept.

1. A power tool comprising: a housing; a main power shaft located withinthe housing; a peristaltic pump assembly positioned within the housingand operably connected to the main power shaft; and an outlet conduitoperably connected to the peristaltic pump assembly and extendingbetween the peristaltic pump assembly and an outlet port in the housingsuch that fluid is forced by the peristaltic pump assembly through theoutlet conduit to a location outside of the housing.
 2. The power toolof claim 1, wherein the peristaltic pump assembly comprises: an arcuatepump casing; a tube positioned along the arcuate pump casing; a rotorand an eccentric shaft operably connected to the main power shaft; andat least one roller rotatably supported by the rotor.
 3. The power toolof claim 2, wherein the peristaltic pump assembly further comprises: apump shaft fixedly connected to the rotor; and a pump gear meshed withthe main power shaft.
 4. The power tool of claim 3, wherein the at leastone roller comprises: a first roller extending outwardly from the rotor;and a second roller extending outwardly from the rotor, the secondroller extending outwardly from the first roller at a location generallyopposite from the location at which the first roller extends outwardlyfrom the rotor.
 5. The power tool of claim 3, wherein: the pump gear ismeshed with a first end portion of the main power shaft; and a secondend portion of the main power shaft is configured for operably driving ashaping component.
 6. The power tool of claim 5, wherein the power toolis configured to rotatably drive a shaping component.
 7. The power toolof claim 3, wherein the outlet conduit extends outwardly of the outletport.
 8. The power tool of claim 7, wherein the outlet conduit and theelastomeric tube are integrally formed.
 9. The power tool of claim 2,wherein the arcuate pump casing comprises a portion of the housing. 10.The power tool of claim 2, further comprising; a check valve positionedbetween the outlet conduit and a first end portion of the elastomerictube.
 11. A power tool comprising: a housing; a main power shaft atleast partially located within the housing; a peristaltic pump assemblyoperably connected to the main power shaft; and an outlet conduitoperably connected to the peristaltic pump assembly and extendingbetween the peristaltic pump assembly and an outlet portion of theoutlet conduit, the outlet portion configured to direct fluid toward apredetermined location.
 12. The power tool of claim 11, wherein theperistaltic pump assembly comprises: an arcuate pump casing; anelastomeric tube positioned along the arcuate pump casing; a rotoroperably connected to the main power shaft; and at least one rollerrotatably supported by the rotor.
 13. The power tool of claim 12,wherein the peristaltic pump assembly further comprises: a pump shaftfixedly connected to the rotor; and a pump gear meshed with the mainpower shaft.
 14. The power tool of claim 12, wherein the at least oneroller comprises: a first roller extending outwardly from the rotor; anda second roller extending outwardly from the rotor, the second rollerextending outwardly from the first roller at a location generallyopposite from the location at which the first roller extends outwardlyfrom the rotor.
 15. The power tool of claim 12, wherein: the pump gearis meshed with a first end portion of the main power shaft; and a secondend portion of the main power shaft is configured for operably driving ashaping component.
 16. The power tool of claim 15, wherein the powertool is configured to rotatably drive the shaping component.
 17. Thepower tool of claim 12, wherein: the arcuate pump casing comprises aportion of a housing; and at least a portion of the main power shaft islocated within the housing.
 18. The power tool of claim 12, wherein theoutlet conduit and the elastomeric tube are integrally formed.
 19. Thepower tool of claim 12, further comprising; a first check valvepositioned between the outlet conduit and a first end portion of theelastomeric tube; and a second check valve positioned between the outletconduit and a second end portion of the elastomeric tube.